Inductive coupling device



Jan. 8, 1929. 7 1,698,609

. R. s. PIPER INDUCTIVE COUPLING: DEVICE Filed July 22. 1924 I \NVENTQR ATTORN EY' Patented Jan. 8, 1929.

UNETED STATES RALPH S. PIPER, OF CHICAGO, ILLINGIS.

INDUCTIVE COUPLING DEVICE.

Application filed July 22,

invention relates improvements in variable inductance apparatus, such as corn- .inonly employed in wireless telegraphic and telepaonic circuits. in the class of circuits much dependence is placed on the operation oi the pr ciple of resonance, as c cterminative of suitable working conditions of one circuit with respect to another. The applic ition of this principle necessitates the use of variable condensers and variable inductance elements and my present invention is more especi lly concerned with the latter type of apparatus, sometimes called iccouplers, etc, according to the character of the connections between the inductance device itself and the circuits of which it forms atent 1,438,854, granted to me Dec. disclosed and claimed a coupling 'nier for use in radio circuits which windings presenting Zones, or areas, close couplingcharacteristics alterother zones in which the coupling b comes progressively looser, and then proessivcl tighter. In this application I ve extended the use oi such a piece of appaand analogous devices, by providing various regions of adjustability between windings that present areas of respective loose and close coupling characteristics. I will describe my invention more particularly in connection with the accompanying drawings, which constitute part of this specification, and in which i is a longitudinal section of a disc form of my invention.

Fig. 2 is an end elevation of the device shown in Fig. l, with certain parts brolren away.

Fig. 3 crosssection of a disk form of my invention.

in Figs. 1 and 2 I have shown a disc mdi fication of the invention. In the disc form a shaft 16 carries a disc 8 securely mounted thereon by collars 74, this disc is made of some pliant non-conducting material and has a number of slots 14, as is usual in such parts in the art, through which a winding is threaded, as shown in Fig. 2. The shaft 16 also carries two sleeves 10, provided with flanges which supportother discs 6 and 7, which are also 01 some resilient material and non-conducting, like hard rubber, these discs are also slotted like disc 8 to retain windings. Disc 6 may be a secondary to a primary on disc 8 and 7 may carry a tickler coil, or other utilizes v riometers, va

1324. Serial NO. 727,446.

winding arrangements may be used, the invention is general that respect.

The sleeves are freely slidable. and rotatable on shaft- 16, but may be fixedin any desired position of adjustment by setscrews 11. These sleeves carry thimbles 9 freely slidable thereon which may also be locked in any position of adjustment by set screws. The thimbles 9 engage the hubs of conical reach members 5 which are headed over the tops, or outer edges of discs 6 and 7. The relation of this beading being such with respect to the disc diameter that the parts be easily sorung together. From the construction as described it will be seen that discs 6, 7 and 8 may be put into very close coupling relation throughout, if desired; furthermore discs 6 and 7 may be sprung away from disc 8 along their oute peripheries while their central areas are still 0 selycoupled to' also 8. In the latter POE 1' of adjustment and 7 will bear against disc 8 somewhat as the bacl: of a saucer, against a table. A further permissible adjusticut would be to slack up set screws 11 after thimbles 9 had been adjusted to bend discs 6 and 7 and slide sleeves G to give any desired opening in the central areas also.

In the form of my invention shown in Fig. '3, 82 is a base plate of impregnated paper, bakelite, hard rubber etc. It carries a central bolt or shaft 85 moulded therein or otherwise fixedly secured thereto. Base plate 82 also carries a hub 88 integral therewith and an integral peripheral bead 89. The latter is used to act as the rest or support of the periphcry of a star shaped coil structure 90, which is made up of a central disc portion and a number of sectors or arms, as in the usual card board spider-web support. I have shown two of these arms 81 and 87 resting on the head 89, the center of the disc 90, or other concavoconvex coil 90, surrounds the hub 88 of the base plate 82, and is surmounted by a true disc coil 80, which also is concentric with hub 88. he coil 90 is given a permanent initial set so that it is ab 'ays convex upwards when resting on head 89 and not under pres sure due to the action of a thumb nut 84 and collar 83. The function of these latter being to compress the two coils 90 and 80 together, when this pressure is removed the resilience of coil 90, assisted by spring 86 returns the system to an open-coupled relation of the two discs, as shown in Fig. 3.

The operation of this form of the invention the outside discs 6' will be understood from the above detailed description of parts. The central portion of disc 90 remains constantly in close coupling with top disc 80, but as nut 84 is turned to clamp the two discs together, the gap between them becomes less and less; however, if desired a packing washer 92 may readily be inserted between the central portions: of the two discs, by running off nut 8d and lifting the top disc 80 off the bolt 85. As shown in Fig. 3, the contact of the two discs is similar to that which exists between a saucer and a table on which it rests. As the winding passes from one arm to the next of disc 90 a small allowance'of freelwire is needed to allow for spreading of these arms when flattened against the other coil.

7 One reason that the above described devices appear to produce especially favorable results in oscillatory circuit adjustments probably depends on the well knownfact that all such circuits require a certain amount of capacity and a certain amount of inductance, depending in amount on the particular circuit. If precisely the right amount of both capacity and inductance could be inserted in the circuit at the first adjustment, evidently the circuit would immediately drop into step with the reactions of the circuits with which it co-operates. In the prior art this right amount'has always been determined by a series of approximations which involve varying the whole amount of the inductance in circuit, but it will be found as a characteristic of the devices described above that they make the necessary adjustment on only a fractional part of the whole amount needed. For many circuits it will be known that at least a given amount of inductance will be needed and that much can be left in circuit without change, thus contributing to the stability of the adjustment. It is a well known property of all kinds of resonant agreement that the nearer conditions are to perfect agreement the easier it is to bring them into complete accord.

a winding carried thereby and opposed tosaid plane faced element.

2. A radio coupler transformer comprising a concavo-convex coil, a plane disc coil'in combination therewith, and means for varying the spacing around the edges of said coils.

3. A radio coupler assemblage comprising two radially wound coils of general disk contour and means for keeping their central portions a fixed distance apart and for varying the distance apart of their peripheral portions.

RALPH s. PIPER. 

